Push-Out Bond Strength of Glass Fiber Endodontic Posts with Different Diameters.

(1) Background: The retention of intraradicular posts is an important factor for the prognosis of endodontically treated teeth. The purpose of this study was to evaluate the push-out bond strength (PBS) of the posts relating to their diameter and region of the root. (2) Methods: A total of 40 premolar teeth (decoronated and root canal-filled) were divided into four groups (n = 10). After post-space preparation, different sizes (1.0, 1.2, 1.5, and 2.0 mm) of glass fiber posts were luted with resin cement into the root canals. After placement, 2 mm thick slices were cut from the roots according to their apical, middle, and coronal regions (n = 116). Push-out tests were carried out in a universal testing machine on each slice. A statistical evaluation of the data was applied. (3) Results: When comparing the diameter, the 2.0 mm posts had the highest PBS (111.99 ± 10.40 N), while the 1.0 mm posts had the lowest PBS (99.98 ± 8.05 N). Divided by the surface of the bonded area, the average PBS value was the highest for the 1.0 mm posts (18.20 ± 1.67 MPa) and the lowest for the 2.0 mm posts (12.08 ± 1.05 MPa). (4) Conclusions: Within the limitations of the study, when comparing the regions of the roots, no significant differences were found among the PBS values of the three regions (p = 0.219). When comparing the diameters, significant differences were shown between the PBS values of the four groups (p = 0.023 and p = 0.003, respectively).

Effect of different parameters utilized for image guided endodontic root canal preparation on temperature changes: an in vitro study.

BACKGROUND: Navigated endodontics is a cutting-edge technology becoming increasingly more accessible for dental practitioners. Therefore, it is necessary to clarify the ideal technical parameters of this procedure to prevent collateral damage of the surrounding tissues. There is a limited number of studies available in published scientific literature referencing the possible collateral thermal damage due to high-speed rotary instruments used in guided endodontic drilling. The aim of our study was to investigate the different drilling parameters and their effect upon the temperature elevations measured on the outer surface of teeth during guided endodontic drilling. METHODS: In our in vitro study, 72 teeth with presumably narrow root canals were prepared using a guided endodontic approach through a 3D-printed guide. Teeth were randomly allocated into six different test groups consisting of 12 teeth each, of which, four parameters affecting temperature change were investigated: (a) access cavity preparation prior to endodontic drilling, (b) drill speed, (c) cooling, and (d) cooling fluid temperature. Temperature changes were recorded using a contact thermocouple electrode connected to a digital thermometer. RESULTS: The highest temperature elevations (14.62 °C ± 0.60 at 800 rpm and 13.76 °C ± 1.24 at 1000 rpm) were recorded in the groups in which drilling was performed without prior access cavity preparation nor without a significant difference between the different drill speeds (p = 0.243). Access cavity preparation significantly decreased temperature elevations (p < 0.01) while drilling at 800 rpm (8.90 °C ± 0.50) produced significantly less heating of the root surface (p < 0.05) than drilling at 1000 rpm (10.09 °C ± 1.32). Cooling significantly decreased (p < 0.01) temperature elevations at a drill speed of 1000 rpm, and cooling liquid temperatures of 4-6 °C proved significantly (p < 0.01) more beneficial in decreasing temperature elevations (1.60 °C ± 1.17) than when compared with room temperature (21 °C) liquids (4.01 °C ± 0.22). CONCLUSIONS: Based on the results of our study, guided endodontic drilling at drill speeds not exceeding 1000 rpm following access cavity preparation, with constant cooling using a fluid cooler than room temperature, provides the best results in avoiding collateral thermal damage during navigated endodontic drilling of root canals.

[Incidence of combination syndrome based on the orthopantomograms made between 2009 és 2014 at the Department of Prosthodontics, University of Pécs, Hungary]. / A kombinációs szindróma gyakorisága a Pécsi Tudományegyetem Klinikai Központ Fogpótlástani Tanszékén a 2009 és 2014 között készült orthopantomogramok alapján.

The treatment of patients having a completely edentulous maxillary arch and lower anterior teeth present is frequent in the dental practice. In these cases some specific changes can be detected in the oral cavity and on orthopantomograms. These signs were summarized and described first by Kelly (1972). Aim of the study was to examine the presence of the specific signs of the combination syndrome among the patients between 2009 and 2014. With the help of the electronic patient registry system used by the University of Pécs, 319 patients were filtered who were diagnosed with anodontia code (K0000 International Classification of Diseases (ICD)) in the examined period. 220 patients' orthopantomograms were evaluated searching for specific symptoms of the combination syndrome. 34 patients had complete edentulous maxilla and anterior teeth in the mandible. 4 patients (11.7%) showed the main sign of the combination syndrome, i.e. the maxillary anterior bone loss. Hypertrophy of maxillary tuberosity (9 cases, 26.4%), extrusion of the lower anterior teeth (6 cases, 17.6%) and great resorption of the distal mandibular ridge (16 cases, 47%) was diagnosed on the X-rays. The clinical examination of three patients supported the radiological findings. The combination syndrome was detectable, but the incidence rate was lower in this population in comparison with the data available in dental scientific publications.